mm/internal.h

   1 /* internal.h: mm/ internal definitions
   2  *
   3  * Copyright (C) 2004 Red Hat, Inc. All Rights Reserved.
   4  * Written by David Howells (dhowells@redhat.com)
   5  *
   6  * This program is free software; you can redistribute it and/or
   7  * modify it under the terms of the GNU General Public License
   8  * as published by the Free Software Foundation; either version
   9  * 2 of the License, or (at your option) any later version.
  10  */
  11 #ifndef __MM_INTERNAL_H
  12 #define __MM_INTERNAL_H
  13
  14 #include <linux/fs.h>
  15 #include <linux/mm.h>
  16 #include <linux/pagemap.h>
  17
  18 /*
  19  * The set of flags that only affect watermark checking and reclaim
  20  * behaviour. This is used by the MM to obey the caller constraints
  21  * about IO, FS and watermark checking while ignoring placement
  22  * hints such as HIGHMEM usage.
  23  */
  24 #define GFP_RECLAIM_MASK (__GFP_RECLAIM|__GFP_HIGH|__GFP_IO|__GFP_FS|\
  25                         __GFP_NOWARN|__GFP_REPEAT|__GFP_NOFAIL|\
  26                         __GFP_NORETRY|__GFP_MEMALLOC|__GFP_NOMEMALLOC)
  27
  28 /* The GFP flags allowed during early boot */
  29 #define GFP_BOOT_MASK (__GFP_BITS_MASK & ~(__GFP_RECLAIM|__GFP_IO|__GFP_FS))
  30
  31 /* Control allocation cpuset and node placement constraints */
  32 #define GFP_CONSTRAINT_MASK (__GFP_HARDWALL|__GFP_THISNODE)
  33
  34 /* Do not use these with a slab allocator */
  35 #define GFP_SLAB_BUG_MASK (__GFP_DMA32|__GFP_HIGHMEM|~__GFP_BITS_MASK)
  36
  37 void free_pgtables(struct mmu_gather *tlb, struct vm_area_struct *start_vma,
  38                 unsigned long floor, unsigned long ceiling);
  39
  40 static inline void set_page_count(struct page *page, int v)
  41 {
  42         atomic_set(&page->_count, v);
  43 }
  44
  45 extern int __do_page_cache_readahead(struct address_space *mapping,
  46                 struct file *filp, pgoff_t offset, unsigned long nr_to_read,
  47                 unsigned long lookahead_size);
  48
  49 /*
  50  * Submit IO for the read-ahead request in file_ra_state.
  51  */
  52 static inline unsigned long ra_submit(struct file_ra_state *ra,
  53                 struct address_space *mapping, struct file *filp)
  54 {
  55         return __do_page_cache_readahead(mapping, filp,
  56                                         ra->start, ra->size, ra->async_size);
  57 }
  58
  59 /*
  60  * Turn a non-refcounted page (->_count == 0) into refcounted with
  61  * a count of one.
  62  */
  63 static inline void set_page_refcounted(struct page *page)
  64 {
  65         VM_BUG_ON_PAGE(PageTail(page), page);
  66         VM_BUG_ON_PAGE(atomic_read(&page->_count), page);
  67         set_page_count(page, 1);
  68 }
  69
  70 extern unsigned long highest_memmap_pfn;
  71
  72 /*
  73  * in mm/vmscan.c:
  74  */
  75 extern int isolate_lru_page(struct page *page);
  76 extern void putback_lru_page(struct page *page);
  77 extern bool zone_reclaimable(struct zone *zone);
  78
  79 /*
  80  * in mm/rmap.c:
  81  */
  82 extern pmd_t *mm_find_pmd(struct mm_struct *mm, unsigned long address);
  83
  84 /*
  85  * in mm/page_alloc.c
  86  */
  87
  88 /*
  89  * Structure for holding the mostly immutable allocation parameters passed
  90  * between functions involved in allocations, including the alloc_pages*
  91  * family of functions.
  92  *
  93  * nodemask, migratetype and high_zoneidx are initialized only once in
  94  * __alloc_pages_nodemask() and then never change.
  95  *
  96  * zonelist, preferred_zone and classzone_idx are set first in
  97  * __alloc_pages_nodemask() for the fast path, and might be later changed
  98  * in __alloc_pages_slowpath(). All other functions pass the whole strucure
  99  * by a const pointer.
 100  */
 101 struct alloc_context {
 102         struct zonelist *zonelist;
 103         nodemask_t *nodemask;
 104         struct zone *preferred_zone;
 105         int classzone_idx;
 106         int migratetype;
 107         enum zone_type high_zoneidx;
 108         bool spread_dirty_pages;
 109 };
 110
 111 /*
 112  * Locate the struct page for both the matching buddy in our
 113  * pair (buddy1) and the combined O(n+1) page they form (page).
 114  *
 115  * 1) Any buddy B1 will have an order O twin B2 which satisfies
 116  * the following equation:
 117  *     B2 = B1 ^ (1 << O)
 118  * For example, if the starting buddy (buddy2) is #8 its order
 119  * 1 buddy is #10:
 120  *     B2 = 8 ^ (1 << 1) = 8 ^ 2 = 10
 121  *
 122  * 2) Any buddy B will have an order O+1 parent P which
 123  * satisfies the following equation:
 124  *     P = B & ~(1 << O)
 125  *
 126  * Assumption: *_mem_map is contiguous at least up to MAX_ORDER
 127  */
 128 static inline unsigned long
 129 __find_buddy_index(unsigned long page_idx, unsigned int order)
 130 {
 131         return page_idx ^ (1 << order);
 132 }
 133
 134 extern int __isolate_free_page(struct page *page, unsigned int order);
 135 extern void __free_pages_bootmem(struct page *page, unsigned long pfn,
 136                                         unsigned int order);
 137 extern void prep_compound_page(struct page *page, unsigned int order);
 138 #ifdef CONFIG_MEMORY_FAILURE
 139 extern bool is_free_buddy_page(struct page *page);
 140 #endif
 141 extern int user_min_free_kbytes;
 142
 143 #if defined CONFIG_COMPACTION || defined CONFIG_CMA
 144
 145 /*
 146  * in mm/compaction.c
 147  */
 148 /*
 149  * compact_control is used to track pages being migrated and the free pages
 150  * they are being migrated to during memory compaction. The free_pfn starts
 151  * at the end of a zone and migrate_pfn begins at the start. Movable pages
 152  * are moved to the end of a zone during a compaction run and the run
 153  * completes when free_pfn <= migrate_pfn
 154  */
 155 struct compact_control {
 156         struct list_head freepages;     /* List of free pages to migrate to */
 157         struct list_head migratepages;  /* List of pages being migrated */
 158         unsigned long nr_freepages;     /* Number of isolated free pages */
 159         unsigned long nr_migratepages;  /* Number of pages to migrate */
 160         unsigned long free_pfn;         /* isolate_freepages search base */
 161         unsigned long migrate_pfn;      /* isolate_migratepages search base */
 162         unsigned long last_migrated_pfn;/* Not yet flushed page being freed */
 163         enum migrate_mode mode;         /* Async or sync migration mode */
 164         bool ignore_skip_hint;          /* Scan blocks even if marked skip */
 165         int order;                      /* order a direct compactor needs */
 166         const gfp_t gfp_mask;           /* gfp mask of a direct compactor */
 167         const int alloc_flags;          /* alloc flags of a direct compactor */
 168         const int classzone_idx;        /* zone index of a direct compactor */
 169         struct zone *zone;
 170         int contended;                  /* Signal need_sched() or lock
 171                                          * contention detected during
 172                                          * compaction
 173                                          */
 174 };
 175
 176 unsigned long
 177 isolate_freepages_range(struct compact_control *cc,
 178                         unsigned long start_pfn, unsigned long end_pfn);
 179 unsigned long
 180 isolate_migratepages_range(struct compact_control *cc,
 181                            unsigned long low_pfn, unsigned long end_pfn);
 182 int find_suitable_fallback(struct free_area *area, unsigned int order,
 183                         int migratetype, bool only_stealable, bool *can_steal);
 184
 185 #endif
 186
 187 /*
 188  * This function returns the order of a free page in the buddy system. In
 189  * general, page_zone(page)->lock must be held by the caller to prevent the
 190  * page from being allocated in parallel and returning garbage as the order.
 191  * If a caller does not hold page_zone(page)->lock, it must guarantee that the
 192  * page cannot be allocated or merged in parallel. Alternatively, it must
 193  * handle invalid values gracefully, and use page_order_unsafe() below.
 194  */
 195 static inline unsigned int page_order(struct page *page)
 196 {
 197         /* PageBuddy() must be checked by the caller */
 198         return page_private(page);
 199 }
 200
 201 /*
 202  * Like page_order(), but for callers who cannot afford to hold the zone lock.
 203  * PageBuddy() should be checked first by the caller to minimize race window,
 204  * and invalid values must be handled gracefully.
 205  *
 206  * READ_ONCE is used so that if the caller assigns the result into a local
 207  * variable and e.g. tests it for valid range before using, the compiler cannot
 208  * decide to remove the variable and inline the page_private(page) multiple
 209  * times, potentially observing different values in the tests and the actual
 210  * use of the result.
 211  */
 212 #define page_order_unsafe(page)         READ_ONCE(page_private(page))
 213
 214 static inline bool is_cow_mapping(vm_flags_t flags)
 215 {
 216         return (flags & (VM_SHARED | VM_MAYWRITE)) == VM_MAYWRITE;
 217 }
 218
 219 /* mm/util.c */
 220 void __vma_link_list(struct mm_struct *mm, struct vm_area_struct *vma,
 221                 struct vm_area_struct *prev, struct rb_node *rb_parent);
 222
 223 #ifdef CONFIG_MMU
 224 extern long populate_vma_page_range(struct vm_area_struct *vma,
 225                 unsigned long start, unsigned long end, int *nonblocking);
 226 extern void munlock_vma_pages_range(struct vm_area_struct *vma,
 227                         unsigned long start, unsigned long end);
 228 static inline void munlock_vma_pages_all(struct vm_area_struct *vma)
 229 {
 230         munlock_vma_pages_range(vma, vma->vm_start, vma->vm_end);
 231 }
 232
 233 /*
 234  * must be called with vma's mmap_sem held for read or write, and page locked.
 235  */
 236 extern void mlock_vma_page(struct page *page);
 237 extern unsigned int munlock_vma_page(struct page *page);
 238
 239 /*
 240  * Clear the page's PageMlocked().  This can be useful in a situation where
 241  * we want to unconditionally remove a page from the pagecache -- e.g.,
 242  * on truncation or freeing.
 243  *
 244  * It is legal to call this function for any page, mlocked or not.
 245  * If called for a page that is still mapped by mlocked vmas, all we do
 246  * is revert to lazy LRU behaviour -- semantics are not broken.
 247  */
 248 extern void clear_page_mlock(struct page *page);
 249
 250 /*
 251  * mlock_migrate_page - called only from migrate_misplaced_transhuge_page()
 252  * (because that does not go through the full procedure of migration ptes):
 253  * to migrate the Mlocked page flag; update statistics.
 254  */
 255 static inline void mlock_migrate_page(struct page *newpage, struct page *page)
 256 {
 257         if (TestClearPageMlocked(page)) {
 258                 int nr_pages = hpage_nr_pages(page);
 259
 260                 /* Holding pmd lock, no change in irq context: __mod is safe */
 261                 __mod_zone_page_state(page_zone(page), NR_MLOCK, -nr_pages);
 262                 SetPageMlocked(newpage);
 263                 __mod_zone_page_state(page_zone(newpage), NR_MLOCK, nr_pages);
 264         }
 265 }
 266
 267 extern pmd_t maybe_pmd_mkwrite(pmd_t pmd, struct vm_area_struct *vma);
 268
 269 /*
 270  * At what user virtual address is page expected in @vma?
 271  */
 272 static inline unsigned long
 273 __vma_address(struct page *page, struct vm_area_struct *vma)
 274 {
 275         pgoff_t pgoff = page_to_pgoff(page);
 276         return vma->vm_start + ((pgoff - vma->vm_pgoff) << PAGE_SHIFT);
 277 }
 278
 279 static inline unsigned long
 280 vma_address(struct page *page, struct vm_area_struct *vma)
 281 {
 282         unsigned long address = __vma_address(page, vma);
 283
 284         /* page should be within @vma mapping range */
 285         VM_BUG_ON_VMA(address < vma->vm_start || address >= vma->vm_end, vma);
 286
 287         return address;
 288 }
 289
 290 #else /* !CONFIG_MMU */
 291 static inline void clear_page_mlock(struct page *page) { }
 292 static inline void mlock_vma_page(struct page *page) { }
 293 static inline void mlock_migrate_page(struct page *new, struct page *old) { }
 294
 295 #endif /* !CONFIG_MMU */
 296
 297 /*
 298  * Return the mem_map entry representing the 'offset' subpage within
 299  * the maximally aligned gigantic page 'base'.  Handle any discontiguity
 300  * in the mem_map at MAX_ORDER_NR_PAGES boundaries.
 301  */
 302 static inline struct page *mem_map_offset(struct page *base, int offset)
 303 {
 304         if (unlikely(offset >= MAX_ORDER_NR_PAGES))
 305                 return nth_page(base, offset);
 306         return base + offset;
 307 }
 308
 309 /*
 310  * Iterator over all subpages within the maximally aligned gigantic
 311  * page 'base'.  Handle any discontiguity in the mem_map.
 312  */
 313 static inline struct page *mem_map_next(struct page *iter,
 314                                                 struct page *base, int offset)
 315 {
 316         if (unlikely((offset & (MAX_ORDER_NR_PAGES - 1)) == 0)) {
 317                 unsigned long pfn = page_to_pfn(base) + offset;
 318                 if (!pfn_valid(pfn))
 319                         return NULL;
 320                 return pfn_to_page(pfn);
 321         }
 322         return iter + 1;
 323 }
 324
 325 /*
 326  * FLATMEM and DISCONTIGMEM configurations use alloc_bootmem_node,
 327  * so all functions starting at paging_init should be marked __init
 328  * in those cases. SPARSEMEM, however, allows for memory hotplug,
 329  * and alloc_bootmem_node is not used.
 330  */
 331 #ifdef CONFIG_SPARSEMEM
 332 #define __paginginit __meminit
 333 #else
 334 #define __paginginit __init
 335 #endif
 336
 337 /* Memory initialisation debug and verification */
 338 enum mminit_level {
 339         MMINIT_WARNING,
 340         MMINIT_VERIFY,
 341         MMINIT_TRACE
 342 };
 343
 344 #ifdef CONFIG_DEBUG_MEMORY_INIT
 345
 346 extern int mminit_loglevel;
 347
 348 #define mminit_dprintk(level, prefix, fmt, arg...) \
 349 do { \
 350         if (level < mminit_loglevel) { \
 351                 if (level <= MMINIT_WARNING) \
 352                         printk(KERN_WARNING "mminit::" prefix " " fmt, ##arg); \
 353                 else \
 354                         printk(KERN_DEBUG "mminit::" prefix " " fmt, ##arg); \
 355         } \
 356 } while (0)
 357
 358 extern void mminit_verify_pageflags_layout(void);
 359 extern void mminit_verify_zonelist(void);
 360 #else
 361
 362 static inline void mminit_dprintk(enum mminit_level level,
 363                                 const char *prefix, const char *fmt, ...)
 364 {
 365 }
 366
 367 static inline void mminit_verify_pageflags_layout(void)
 368 {
 369 }
 370
 371 static inline void mminit_verify_zonelist(void)
 372 {
 373 }
 374 #endif /* CONFIG_DEBUG_MEMORY_INIT */
 375
 376 /* mminit_validate_memmodel_limits is independent of CONFIG_DEBUG_MEMORY_INIT */
 377 #if defined(CONFIG_SPARSEMEM)
 378 extern void mminit_validate_memmodel_limits(unsigned long *start_pfn,
 379                                 unsigned long *end_pfn);
 380 #else
 381 static inline void mminit_validate_memmodel_limits(unsigned long *start_pfn,
 382                                 unsigned long *end_pfn)
 383 {
 384 }
 385 #endif /* CONFIG_SPARSEMEM */
 386
 387 #define ZONE_RECLAIM_NOSCAN     -2
 388 #define ZONE_RECLAIM_FULL       -1
 389 #define ZONE_RECLAIM_SOME       0
 390 #define ZONE_RECLAIM_SUCCESS    1
 391
 392 extern int hwpoison_filter(struct page *p);
 393
 394 extern u32 hwpoison_filter_dev_major;
 395 extern u32 hwpoison_filter_dev_minor;
 396 extern u64 hwpoison_filter_flags_mask;
 397 extern u64 hwpoison_filter_flags_value;
 398 extern u64 hwpoison_filter_memcg;
 399 extern u32 hwpoison_filter_enable;
 400
 401 extern unsigned long vm_mmap_pgoff(struct file *, unsigned long,
 402         unsigned long, unsigned long,
 403         unsigned long, unsigned long);
 404
 405 extern void set_pageblock_order(void);
 406 unsigned long reclaim_clean_pages_from_list(struct zone *zone,
 407                                             struct list_head *page_list);
 408 /* The ALLOC_WMARK bits are used as an index to zone->watermark */
 409 #define ALLOC_WMARK_MIN         WMARK_MIN
 410 #define ALLOC_WMARK_LOW         WMARK_LOW
 411 #define ALLOC_WMARK_HIGH        WMARK_HIGH
 412 #define ALLOC_NO_WATERMARKS     0x04 /* don't check watermarks at all */
 413
 414 /* Mask to get the watermark bits */
 415 #define ALLOC_WMARK_MASK        (ALLOC_NO_WATERMARKS-1)
 416
 417 #define ALLOC_HARDER            0x10 /* try to alloc harder */
 418 #define ALLOC_HIGH              0x20 /* __GFP_HIGH set */
 419 #define ALLOC_CPUSET            0x40 /* check for correct cpuset */
 420 #define ALLOC_CMA               0x80 /* allow allocations from CMA areas */
 421 #define ALLOC_FAIR              0x100 /* fair zone allocation */
 422
 423 enum ttu_flags;
 424 struct tlbflush_unmap_batch;
 425
 426 #ifdef CONFIG_ARCH_WANT_BATCHED_UNMAP_TLB_FLUSH
 427 void try_to_unmap_flush(void);
 428 void try_to_unmap_flush_dirty(void);
 429 #else
 430 static inline void try_to_unmap_flush(void)
 431 {
 432 }
 433 static inline void try_to_unmap_flush_dirty(void)
 434 {
 435 }
 436
 437 #endif /* CONFIG_ARCH_WANT_BATCHED_UNMAP_TLB_FLUSH */
 438 #endif  /* __MM_INTERNAL_H */